Metaethics is a branch of ethics that investigates the fundamental nature of moral properties, values, and judgments, rather than focusing on specific moral issues or the application of moral principles.

Moral realism asserts that moral properties exist independently of human minds and are not dependent on individual beliefs or preferences.

Moral subjectivism maintains that moral judgments are based solely on the individual's subjective beliefs and preferences, rather than any objective criteria.

Utilitarianism is a consequentialist theory that evaluates the morality of an action based on its overall consequences, aiming to maximize happiness or minimize suffering.

The term 'ought' is often used in moral contexts to express a sense of moral obligation or duty, rather than logical necessity, personal preference, or causal relationships.

Virtue ethics focuses on the cultivation of virtuous character traits, such as honesty, courage, and compassion, as the foundation for ethical behavior.

The 'is-ought' problem highlights the challenge of deriving moral judgments (what ought to be) from purely factual statements (what is).

Deontology, particularly Kantian ethics, emphasizes the importance of following universal moral principles, such as respect for persons and justice, regardless of the consequences.

Moral nihilism is the philosophical position that moral values are ultimately meaningless and non-existent, rejecting the idea of objective moral truths.

Virtue ethics places significant emphasis on the intentions and character of the agent, rather than solely focusing on the consequences of the action.

C.L. Stevenson, a 20th-century philosopher, is credited with introducing the term 'metaethics' to refer to the philosophical study of the nature and foundations of morality.

Kantian ethics, developed by Immanuel Kant, emphasizes the importance of acting in accordance with universal moral principles derived from reason, rather than personal desires or consequences.

Moral relativism is the philosophical position that moral values are not objective or universal, but rather vary depending on the individual, culture, or historical context.

Utilitarianism, particularly classical utilitarianism, emphasizes the importance of maximizing overall happiness or well-being as the primary moral goal.

Moral particularism is the philosophical position that moral judgments should be made on a case-by-case basis, taking into account the specific circumstances and context, rather than relying on general moral principles.